John Yates, assistant commissioner of the Metropolitan police, leaves after giving evidence to a House of Commons committee looking into phone hacking. Photograph: Carl Court/AFP/Getty Images

John Yates's time in charge of the investigation into the News of the World phone-hacking allegations will be regarded as one of the least successful chapters in a Met career spanning more three decades.

The 51-year-old has become the force's public face through a series of high-profile operations, most notably the tortuous and futile 16-month investigation into the Labour "cash-for-honours" allegations.

And with the commissioner, Sir Paul Stephenson, off work through illness it was Yates, who had been widely tipped as a potential successor, who was appointed acting deputy commissioner.

In 2009 he was commissioned by the Met to conduct a brief review of how it had investigated News International after the Guardian claimed hundreds of voice messages had been hacked into.

But as scrutiny of the police operation has intensified there have been growing concerns about Yates's role, amid claims he failed to persuade the public the police were treating the allegations seriously.

Born in Liverpool and educated at Marlborough and King's College London, Yates joined the Met in 1981 and spent time in uniform before rising through the ranks.

Popular among rank-and file-officers, Yates is close to Stephenson, and had cemented his reputation as a safe pair of hands, taking the lead in a number of high-profile cases.

In 2002, he took charge of the trial of the former royal butler Paul Burrell for the alleged theft of Princess Diana's possessions. The case eventually collapsed, following an intervention by the Queen.

He also travelled to Brazil to meet the parents of Jean Charles de Menezes, the electrician shot dead in July 2005 at Stockwell underground station in south London by anti-terrorism officers after being mistaken for a would-be suicide bomber.

As head of the special inquiry squad, nicknamed the "celebrity squad", Yates handled a series of sensitive cases, notably the conviction for perjury of the novelist and former Conservative party chairman Lord Archer, the investigation of the television presenter John Leslie over claims of rape and the Who Wants To Be a Millionaire? fraud case.

In 2006 he was appointed assistant commissioner taking over from Bob Quick as head of counter-terrorism in 2009 following an embarrassing security breach.

But it was the cash-for-honours investigation that thrust him most prominently into the limelight. The 16-month inquiry ended in July 2007 with no charges brought.

Senior Labour figures said Yates and his officers – who carried out a dawn swoop on Downing Street aide Ruth Turner and arrested Tony Blair's friend and envoy Lord Levy – had been heavy-handed.

Yates, however, insisted he had simply been following the evidence and also noted that his officers had at times received "less than full co-operation" from those allegedly involved.